Spectrum allocation system and method for multi-band wireless RF data communications

ABSTRACT

A dual band spectrum allocation system and method for wireless data communications uses discrete bands for upstream and downstream data communications. A preferred embodiment uses unlicensed UNII bands for license-free data transmissions from a subscriber to a hub, and uses relatively interference free licensed bands for data transmissions from a hub to subscribers, thereby allowing use of greater bandwidth, simplifying system licensing and reducing filtering requirements for subscribers.

TECHNICAL FIELD

The present invention generally relates to wireless RF datacommunications, and specifically to spectrum allocation systems andmethods for multi-band wireless RF data communications.

BACKGROUND OF THE INVENTION

Currently, there are several so-called “last mile” and “last foot” datatransmission systems which are designed to deliver high speed and/orhigh data capacity from the internet backbone to an end user or toprovide high speed data communications in a campus-like setting. Severalsuch systems use RF transmissions to replace copper wire or fiber opticcables. Some of these fixed wireless data communications systems arecalled point-to-point or point-to-multipoint systems and operate invarious licensed and unlicensed RF bands. Point-to-point systems,typically have a pair of transceivers communicating only with eachother, for example from one building to another. Point to multi-pointsystems communicate between a hub station, or the like and a number ofsubscriber stations, or the like. For example, such a point tomulti-point system may broadcast from a central tall building to anumber of shorter buildings.

Typically either of these systems utilize one frequency band ofoperation, generally, transmitting and receiving on separate frequencieswithin the same basic band employing frequency division duplexing (FDD).Such prior art data communication systems operate entirely within oneregulated band. These prior art systems employ a subchannel scheme forupstream and downstream in which the frequencies of such subchannels arerelatively closely spaced. That adjacency requires extensive use offilters resulting in increased size and cost for data communicationsystems, particularly for subscriber stations. The band utilized forcommunication in such prior art systems may be a licensed band or it maybe an unlicensed band. Generally, as employed herein, unless otherwisenoted, a band is a generally contiguous portion of the electromagneticspectrum which is regulated by a governmental entity, such as theFederal Communications Commission (FCC) for the United States, generallyunder a single designation such as those described below.

Another technique which is used to enable communications within a bandof operation is time division duplexing (TDD), whereby a base station orhub transmits part of the time on a frequency, and then a subscribertransmits part of the time on the same frequency, thereby sharing thesame frequency. Such a system may employ the entire bandwidth availablefacilitating broadband communications rather than splitting theavailable bandwidth between upstream and downstream signals as isrequired in FDD. A disadvantage in a TDD system is that a large amountof coordination is required, resulting in inefficiencies. Thebits-per-megahertz efficiency of the data communicated in a TDD systemis greatly degraded because time sharing takes a lot of coordinationand/or processing power. Further, units in a TDD system are typicallynot able to operate autonomously, they must be directed from a centralunit such as a hub station in order to provide the aforementionedcoordination.

In FDD, a base station may simultaneously transmit and receive, and asubscriber station may simultaneously transmit and receive. Thisprovides a benefit in efficiency with this type of system in that thesystem does not require a lot of processing power or coordination todetermine when to transmit and when to receive as with TDD. Thisinherent efficiency in an FDD system makes good use of spectrum inwireless data communications when larger amounts of spectrum areavailable. However, the upstream and downstream communicationsfrequencies are typically in the same regulated band. FDD typicallyneeds a reasonable amount, about one percent of bandwidth, oftransmission to reception spacing between upstream and downstreamfrequencies.

In the prior art, the radio of a hub-station or subscriber station mayinclude a duplexer, which employs filters to filter the upstream out ofthe downstream, and vice versa. In prior art data communicationstransceivers, a transmitted signal, and even transmit induced noise canenter the transceiver's receiver, because the receiver is intended toreceive a very weak signal. So in the prior art very sophisticatedfilter systems are required to keep the transmit signal or interferencecaused by the transmit signal out of the receiver.

The Multichannel Multipoint Distribution Service (MMDS) is an FCCregulated communications band that operates in the microwave portion ofthe radio spectrum, between 2.1 and 2.7 GHz. MMDS. Also known aswireless cable, this band was initially intended for use as a substitutefor conventional coaxial cable television. However, the MMDS band hascome under wide use for data communication services due to deregulationthat allows cable TV companies to provide Internet services. Narrowbandchannels within MMDS can be used by subscribers to transmit signals tothe network. Such narrowband channels were originally intended for usein an educational setting (so-called wireless classrooms). Thusly, theInstructional Television Fixed Service (ITFS) band interleaves with theMMDS band. In ITFS, the FCC allows use of either polarity fortransmissions by a license-holder, while in MMDS use of the samespectrum, the FCC requires licensing of the polarity as well as thefrequency used for transmission.

Other FCC licensed and regulated bands include the following. WirelessCommunications Services (WCS) occupy two fifteen MHz wide bands at 2.3GHz. WCS is intended for wireless data services. Digital ElectronicMessage Services (DEMS) at the 24.25 to 24.45 and 25.05 to 25.25 GHzbands offer high data capacity over short distances, particularly usefulfor providing broadband data services to businesses in dense, urbanareas or in a campus environment. Local Multipoint Distribution Services(LMDS) employ the 27.5 to 29.5 GHz and 31.0 to 31.3 GHz bands. WirelessLocal Loop and fixed wireless data connection systems such aspoint-to-point or point-to-consecutive point systems operate in thesebands. So called Fixed Wireless Local Loop Services occupy the 38.6 GHzto 40 GHz band.

Problematically, there are only a limited number of licensed bands inany geographic area. Also, in these licensed spectrum bands, limitedspectrum problems arise where the licensee may not have as muchbandwidth in a particular market as needed to provide broadband servicesdesired by the licensee's customers. Also, problems arise where alicensee has spectrum, but this spectrum is not ideal in terms of atransmit/receive frequency pair. For example, certain amount ofspectrum, as a percentage of bandwidth, between the upstream and thedownstream (i.e. transmit and receive frequencies) is required to allowstate of the art filters to properly operate. Many spectrum licensees donot have sufficient spectrum bandwidth available to provide thisseparation between employed frequencies.

In 1997 the FCC created a wireless arena called Unlicensed NationalInformation Infrastructure (UNII). System operators are free to operatewireless equipment in three sub-bands (5.15 to 5.25 GHz, 5.25 to 5.35GHz and 5.725 to 5.825 GHz) without acquiring a licensed frequencyspectrum. The FCC specifies the conditions for operating wirelessequipment in the UNII frequency band. However, operators are notprotected from possible interference from other UNII operatorstransmitting in the vicinity or even other systems or devices whichutilize the same frequencies.

A problem that many wireless data communication system operators face isa need to provide the highest possible data rates to subscriber units.One prior art method of providing greater through-put in licensed bandsis to have a very large channel bandwidth providing data to thesubscriber. To increase through-put to a particular subscriber unit, thebandwidth must necessarily increase or the modulation scheme that isused has to become more complicated. Problematically, bandwidth islimited in both the licensed and unlicensed bands and using a highermodulation scheme causes an increase in the necessary signal to noiseratio or carrier to interference ratio (C/I). For example, increasingfrom a quadrature phase shift keying (QPSK) modulation to a 16quadrature-amplitude modulation (16QAM), which doubles the throughput,requires a 6 dB increase in C/I. Problematically, such increases in C/Imay not be practical, particularly in the unlicensed bands where asignificant amount of interference may be present.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to systems and methods for providingwireless data transmission spectrum allocation by utilizing separatebands for upstream and downstream wireless data communication. In apreferred embodiment the present invention takes the form of a dual bandspectrum allocation system and method for wireless data communicationsusing unlicensed UNII bands for license-free data transmissions from asubscriber to a hub, and using relatively interference-free licensedbands for data transmissions from a hub to subscribers, thereby allowinguse of greater bandwidth.

The present invention enables the use of wireless spectrum for digitaldata communication, such as Internet access or other connections such asEthernet, between points such as campus building's or the like. Thepresent invention is intended to enable use of spectrum that is nototherwise useable for high data rate communication and enables use oflimited spectrum where there is not enough bandwidth available to alicensee to transmit the amount of data that is required by the licenseeor its customers. As pointed out above, continuous spectrum, whichprovides sufficient bandwidth for a proper data rate to be passed by awireless data communications system, is somewhat rare or at leastdifficult and costly to acquire. The present invention provides asolution for licensees with spectrum congestion and spectrum limitationproblems.

The present invention allows an operator to use any band to which theoperator has access. If the operator has licenses in more than one bandthe present invention allows the operator to make efficient use of theselicenses. Similarly, if an operator has a license in only one band, theoperator can enhance use of the available spectrum in the licensed bandby employing unlicensed bands, such as the UNII bands for one directionof communication in accordance with the present invention. For example,a licensee may employ its relatively interference-free licensed spectrumbandwidth for high speed, relatively broadband, transmissions from a hubstation to subscriber stations while employing an unlicensed band suchas the 5.8 GHz band of the UNIT bands for communications fromsubscribers to the hub. This UNIT upper band is 100 megahertz wide andis sparsely used. In most markets there are relatively few or notransmissions in this band.

Generally, Internet or other network traffic is asymmetric, that is tosay, there is more traffic coming from the network to subscribers thanfrom subscribers to the network. Therefore, in the present system andmethod the less noisy licensed band frequency is preferably used totransmit data downstream from the hub to the subscriber while thenoisier unlicensed band frequency is preferably used to transmitupstream data from a subscriber to the hub. However, one embodiment ofthe present system and method, by employing the relatively underusedunlicensed band at 5.8 GHz, is adaptable to allow relatively highcapacity data transmissions from a subscriber to the hub, as necessary.

By utilizing separate bands, particularly bands separated by an octaveor more, the present invention increases the efficiency and capacity ofa wireless data communication system by allowing use of the fullbandwidth available, in each band, to an operator. As used herein, afrequency octave is a doubling of frequencies. In other words, an octaveis an interval between two frequencies having a ratio of two-to-one. Forexample, a downstream transmission made on a one GHz frequency would beseparated by one octave from an upstream transmission made on a two GHzfrequency. Prior art wireless RF data communication systems do not useover one octave of separation between transmit and receive frequencies.Generally, this would require the use of spectrum from separate bands.Typically, in the prior art, FDD frequency separation is less than onepercent of frequency. For example prior art FDD transmission frequenciesat around one GHz would traditionally be separated by less than ten MHz

The present invention allows spectrum, which does not have sufficientbandwidth to provide one percent frequency separation between upstreamand downstream frequencies, as typically required to use FDD, to be usedfor broadband data transmission. The present system and methodpreferably qualifies a geographical area which may not have been optimalbased on its available line of sight and licensee's spectrum bandwidthfor relatively broadband data communications.

The present inventive point to multi-point radio transmission system isintended to transmit data from one point to multiple points via wirelessdigital radio, preferably from a base or hub station to a number ofsubscriber stations, with efficient use of spectrum and at as low a costas possible. This efficiency is particularly enhanced in a point tomultipoint system due to sharing of the cost for hub equipment and siteor building top, as well as sharing hub operating expenses such aselectricity, among multiple subscribers.

Whereas the present invention uses separate bands of operation to carryout upstream and downstream data transmission, the present inventionnecessarily addresses some distinctive technical problems. A hub andsubscriber stations embodying the present invention each preferablyemploys a multi-band antenna, preferably capable of employing multiplepolarities in all bands. Preferably, this antenna is a dual band antennacapable of employ two orthogonal polarities such as horizontal andvertical polarities in both bands. This dual band antenna preferablyemploys relatively the same gain and footprint for the antenna beams ofboth bands. Preferably, the forward gain, beam width and the reverseside lobe isolation for the antenna beams are similar so that thefootprint for the upstream beam is similar to the footprint for thedownstream beam, even though the bands of operation are separated by anoctave.

An embodiment of the present invention also preferably employs a dualband duplexer. Such a duplexer may be made up of, by way of example,discrete circuit components, an integrated circuit or a rectangularwaveguide assembly. A waveguide based dual band duplexer preferablyemploys two different size waveguide components, on the order of afactor of two. Preferably, the duplexer provides low insertion losswhile low in cost and having a small package size.

Embodiments of the present invention preferably use very diverseportions of spectrum for upstream and downstream data communication,this addresses some of the spectrum limitations and the congestionproblems detailed above. Further, the present invention enables theefficient use of the spectrum because it prevents interference betweentransmit and receive signals without requiring exotic filters. Thepresent dual band approach overcomes the forestated problem of atransmitted signal, or noise induced thereby, entering a transceiver'sreceiver, because as bands are further separated in the electromagnetic(EM) spectrum, the transmitter and receiver of a transceiver do notinterfere with one another. In accordance with the present invention,transmit and receive signals occupy different parts or bands of the EMspectrum, preferably separated by at least an octave of frequency. Sopreferably need for filtering is greatly reduced. As a result offiltering being reduced, the present invention enables the size of adata communications device to be reduced and the cost of the device tobe reduced.

When employing two separate bands, filtering requirements for one bandmay be greater than the filtering requirements for the other band. Thismay be due to one frequency of operation being widely used, for similarand/or different purposes, or an adjacent frequency band that has tightregulatory specifications. For example, some bands, such as WCS, have anadjacent band, such as Digital Audio Radio Satellite (DARS), that havemore stringent rules, in this example due to WCS being a terrestrialband and DARS being a satellite band. By using a relatively noisierband, such as the UNII band, for upstream transmissions, a preferredembodiment of the present invention enables an operator to use the moreexpensive and complicated filter in the base station, and the lessexpensive, smaller filters in subscriber stations. This is economicallyadvantageous in a point to multi-point system since only one large,expensive filter is needed at the base station.

The present invention has great advantages related to frequencycoordination and licensing. Typically in a point to multi-point system,a service provider is required to coordinate a base station so it doesnot interfere with or is received by subscribers in adjacent markets.Additionally, in prior art licensed spectrum data communication systemseach of the subscriber stations must be included in an interferencestudy. Typically, the maximum ground elevation of the highest subscriberin a given sector is used in conjunction with power addition of all ofthe subscribers in the system, transmitting at the same time, to analyzeinterference to any adjacent market. In accordance with a preferredembodiment of the present system, subscribers transmit on an unlicensedband and thus can transmit without benefit of a license. So, a serviceprovider employing the present system and method does not need to make afrequency coordination study for all of the subscriber area. Preferably,use of a licensed band by a hub station for downstream transmissionsaffords a degree of protection from interference by other systems.Therefore, a provider employing the present system and method shouldonly be required to perform frequency coordination for the base station.A related advantage is that as subscribers are added, a provider shouldnot need to refine its frequency plan.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWING

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawing, in which:

FIG. 1 is a diagrammatic illustration of a wireless data communicationsystem employing the present spectrum allocation system and method formulti-band wireless RF data communications;

FIG. 2 is a diagrammatic illustration of an embodiment of a subscriberstation employing dual band wireless data communication in accordancewith the present invention; and

FIG. 3 is a diagrammatic illustration of an embodiment of a hub stationemploying dual band wireless data communication in accordance with thepresent invention.

DETAILED DESCRIPTION

The present systems and methods for multi-band wireless RF datacommunications enables communication of upstream data on one band ofoperation while downstream data is communicated on a different band ofoperation. These bands are preferably separated by more than one percentbandwidth and in a preferred embodiment are separated by at least oneoctave of bandwidth. Specifically one preferred embodiment of thepresent invention utilizes one regulated band for downstreamcommunications such as from a hub station to subscriber stations and anentirely different regulated band for communication in the otherdirection, these bands preferably employ a magnitude of separation,thereby minimizing filtering problems and as a result minimizing sizeand cost of communication stations. The two bands may both be licensedbands or both may be unlicensed bands. However, in one preferredembodiment, one band is a licensed band while another is an unlicensedband.

FIG. 1 is a diagrammatic illustration of a point to multi-point datacommunications system 100 employing an embodiment of the presentspectrum allocation system and method for multi-band wireless RF datacommunications. FIG. 1 shows base station 10 in wireless datacommunication with multiple subscriber systems S1 to Sn. In accordancewith the present system and method any number of subscribers S1 to Snmay be present. The present system and method employ downstream (i.e.from the hub to subscribers) wireless data transmissions 102 and 104 inat least one band of operation, preferably a relativelyinterference-free licensed band such as MMDS, ITFC or WCS whiletransmissions 101 and 103 in the upstream direction (i.e. fromsubscriber to the hub) take place in at least one license-free band,such as the UNIT bands. The bands of operation for the present inventionare preferably separated by more than the normal degree of separationbetween upstream and downstream frequencies as employed in prior artFDD. Preferably, the frequencies of operation for upstream transmissions101 and 103 and the frequencies of operation for downstreamtransmissions 102 and 104 are in separate bands of operation, preferablyregulated bands. Compensation for interference 107 with reception ofupstream communications is preferably carried out by a single filter athub station 10, while interference 108 and 109 with reception of therelatively high data-volume downstream transmissions is relatively minordue to the preferable employment of a relatively interference-freelicensed band. This allows the aforementioned use of a single expensiveand/or complicated filter at the base station, and the use of lessexpensive, smaller filters in subscriber stations.

The present systems and methods preferably employ dual band antennas,and dual band duplexers in both types of stations, hub station 10 andsubscriber stations S1 to Sn. Referring to FIG. 2, an embodiment ofsubscriber unit 200 uses multi-band antenna 201, preferably capable ofemploying multiple polarities in all bands. Preferably, antenna 201 is adual band antenna also capable of employing two orthogonal polaritiessuch as horizontal and vertical polarities. Dual band antenna 201, asdiscussed previously, preferably normalizes the gain of the two bands.Dual band antenna 201 preferably matches the antenna patterns preferablyby matching the pattern beam width, side lobes and front to backfootprint as much as possible, so the footprint of operation matches inthe upstream and the downstream direction as much as possible, eventhough the bands of operation are preferably separated by an octave.Alternatively, separate antenna beams for upstream and downstream datacommunications may be employed to avoid multipath effects or the likeand/or to facilitate non-line-of-sight communications. Regardless, thepresent invention preferably utilizes an antenna that fits packagingrequirements for subscriber stations (i.e. compact size for use in asubscribers available space) while operating in both bands.

Preferably subscriber station 200 employs a multi-band duplexer 202.Duplexer 202 preferably accommodates upstream and downstreamcommunications on at least two greatly different bands of operation. Apreferred embodiment duplexer 202 operates in two separate bands ofoperation, as opposed to transmitting and receiving on frequencieswithin the same band of operation, as with prior art duplexers. Duplexer202 may be made up of discrete circuit components, may be embodied in anintegrated circuit, may comprise a rectangular waveguide assembly or maybe made up of other combinations of components and elements capable ofcarrying out duplexing in accordance with the present invention. Awaveguide based dual band duplexer employs two different size waveguidecomponents. For a preferred duplexer using frequencies in bandsseparated by an octave, the waveguide size difference is on the order ofa factor of two. Preferably, the duplexer provides low insertion losswhile being low in cost and having a small package size. Less expensiveduplexers 202, which may have integrated filters with fewer poles, maybe employed in subscriber stations 200, when compared to a hub station,thereby lowering the cost of subscriber stations 200, making the overallsystem less expensive.

Subscriber station 200 preferably employs intermediate frequency (IF)converters 203 (preferably employing heterodyne techniques), digital toanalog (D/A) processing circuits 204 and analog to digital (A/D)processing circuits 205. Preferably, incoming signals are converted froman analog RF signal to a digital signal for use by customer premisesequipment (CPE) 206, which may include further networking equipmentserving multiple users. Preferably, received signals are broken intotheir MAC layer and PHY layer components for use by conventionalnetworking protocols such as Ethernet to communicate with CPE 206. Fortransmitting, signals originate from CPE 206 as a digital Ethernetsignal or the like and are converted to an RF signal for transmission.The signal is imposed on a carrier signal, preferably produced by avoltage controlled oscillator, or the like (not shown). Preferably theoutput signal is passed through a power amplifier set (not shown), whichdirectly drives antenna output.

Filtering to allow dual band operation is largely handled withinduplexer 202. However, additional filters 207 associated with theaforementioned IF circuitry, specifically digital filtering, known asfinite impulse response (FIR) filtering, and also discrete filteringsuch as surface acoustical wave (SAW) filtering, may be carried out byRF filters 207 before and/or after D/A and A/D conversion. Whereas, inaccordance with the present invention, a band with less interference andthus less filtering requirements is used to transmit from the hub tosubscriber station 200, the subscriber station preferably need not makeextensive use of filtering or may only employ less costly filters forreception.

Turning to FIG. 3, although the architecture of base station 300 issomewhat similar to that of subscriber station 200, technical challengesspecific to a base station 300 arise. Preferably, hub 300 employs amulti-lobe antenna assembly with each lobe comprising a dual bandantenna 301. Similar to subscriber station, 200, the pattern of dualband antenna 301, the side lobes, gain and front to back ratio ofantenna beams for the two different bands employed by the hub fortransmitting and receiving are preferably matched as close as possibleto the same gain and pattern of the complimentary subscriber stationantenna beam patterns. In short, the footprint of a reception antennabeam pattern preferably approximates the footprint for a transmissionantenna beam pattern for both hub antenna 301 and subscriber stationantenna 201, such that the beam patters for both stations aresubstantially co-spatial. Alternatively, separate antenna beams forcommunications from and to hub 300 may be employed to facilitatenon-line-of-sight communication and/or to avoid multipath effects, orthe like.

Hub duplexer 302 of preferred embodiment hub 300 is also a multi-bandduplexer enabling use of at least two different transmit and receivebands. However, base station 300 may utilize a more elaborate duplexer302, e.g. having a greater number of poles, while maintaining lowinsertion loss. A preferred embodiment of duplexer 302 operates inseparate bands of operation, as opposed to prior art duplexers whichtransmit and receive on frequencies within a single band of operation.Embodiments of duplexer 302 may be made up of discrete circuitcomponents, may comprise an integrated circuit or may employ arectangular waveguide assembly which may be made up of two or moredifferent size waveguide components. Preferably, duplexer 302 provideslow insertion loss, is low in cost and is compactly packaged.Additionally, more elaborate filtering is preferably used in conjunctionwith base station dual band duplexer 302.

Similar to subscriber station 200, an embodiment of hub 300 employs IFcircuitry 303 using heterodyne techniques, A/D converters 305, and D/Aconverters 304 to enable communication via network 306. Network 306 maybe the Internet backbone, an intranet, an Ethernet network for a campusor the like, a cable network, public switched telephone network (PSTN),a nationwide service network, or other public or private network.Preferably, incoming signals are converted from an analog RF signal to adigital signal employing A/D converter 305 for use by Network 306.Preferably, signals received by base station 300 are broken into theirMAC layer and PHY layer components for use by conventional networkingprotocols such as Ethernet to communicate with Network 306. Fortransmitting, signals originating from Network 306 as digital signalsare converted to RF signals for transmission by D/A converter circuitry304 and IF/RF circuitry 303.

Filtering at the base station to allow dual band operation is alsolargely handled within duplexer 302. Additional filters 307 associatedwith the aforementioned IF circuitry, which may include digital FIRfiltering and discrete SAW filtering may be carried out before and/orafter D/A and A/D conversion. At base station 300, the present inventionutilizes a reduced number of, or preferably a single, more complicatedand expensive filter, which may have more poles or more selectivity andwhich may or may not be incorporated into duplexer 302. Because one basestation is supporting multiple subscriber stations overall cost of thesystem is reduced, since a single more expensive filter is used at basestation 300 while lower cost filters are used at multiple subscriberstations 200.

As will be appreciated by those skilled in the art functionality ofvarious components in both subscriber station 200 and/or hub station 300of the present system may be integrated into fewer, or even singularcomponents. Conversely, components may be separated. For example,filters, described above as incorporated in duplexers 202 and 302, maybe separate components deployed separately from or in conjunction withduplexers 202 and 302.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

1. A method for increasing capacity of a wireless data communicationsystem, said method comprising the steps of: receiving, at a subscriberstation, data on a first frequency in a frequency band expected toexperience low interference; transmitting, at said subscriber station,data on a second frequency in a frequency band expected to experiencehigh interference, wherein said low interference frequency band and saidhigh interference frequency are separated by at least one octave; andwherein at least a portion of said receiving and at least a portion ofsaid transmitting occur at the same time.
 2. The method of claim 1wherein said data is frequency division duplexed.
 3. The method of claim1 further comprising: receiving, at a base station, data on said secondfrequency in said interference frequency band expected to experiencehigh interference; transmitting, at said base station, data on saidfirst frequency in said frequency band expected to experience lowinterference; wherein said first frequency and said second frequency areseparated by at least one octave.
 4. The method of claim 3 wherein atleast a portion of said receiving at a base station and at least aportion of said transmitting at a base station occur at the same time.5. The method of claim 3 wherein said data is frequency divisionduplexed.
 6. The method of claim 3 wherein said base station performshigher order filtering on signals received at said base station thansaid subscriber station performs on signals received at said subscriberstation.
 7. The method of claim 6 wherein the filtering performed atsaid base station is performed by a multi-pole filter.
 8. The method ofclaim 6 wherein said subscriber station performs lower order filteringon signals received at said subscriber station than said base stationperforms on signals received at said base station.
 9. The method ofclaim 8 wherein the filtering performed at said subscriber station isperformed by finite impulse response (FIR) filtering.
 10. The method ofclaim 8 wherein the filtering performed at said subscriber station isperformed by surface acoustical wave (SAW) filtering.
 11. The method ofclaim 1 wherein said interference frequency band expected to experiencelow interference is determined to be low interference and saidinterference frequency band expected to experience high interference isdetermined to be high interference according to regulation of each ofsaid frequency bands by a governmental entity.
 12. The method of claim11 wherein said governmental entity is the FCC.
 13. A method forincreasing capacity of a wireless data communication system, said methodcomprising the steps of: transmitting, at a base station, data on afirst frequency in a frequency band expected to experience lowinterference; receiving, at said base station, data on a secondfrequency in a frequency band expected to experience high interference;wherein said first frequency and said second frequency are separated byat least one octave; and wherein at least a portion of said receivingand at least a portion of said transmitting occur at the same time. 14.The method of claim 13 wherein said data is frequency division duplexed.15. The method of claim 13 further comprising: receiving, at asubscriber station, data on said first frequency in said frequency bandexpected to experience low interference; transmitting, at saidsubscriber station, data on said second frequency in said frequency bandexpected to experience high interference; wherein said first frequencyand said second frequency are separated by at least one octave.
 16. Themethod of claim 15 wherein at least a portion of said receiving at asubscriber station and at least a portion of said transmitting at asubscriber station occur at the same time.
 17. The method of claim 15wherein said data is frequency division duplexed.
 18. The method ofclaim 15 wherein said base station performs higher order filtering onsignals received at said base station than said subscriber stationperforms on signals received at said subscriber station.
 19. The methodof claim 18 wherein the filtering performed at said base station isperformed by a multi-pole filter.
 20. The method of claim 19 wherein thefiltering performed at said subscriber station is performed by surfaceacoustical wave (SAW) filtering.
 21. The method of claim 18 wherein saidsubscriber station performs lower order filtering on signals received atsaid subscriber station than said base station performs on signalsreceived at said base station.
 22. The method of claim 21 wherein thefiltering performed at said subscriber station is performed by finiteimpulse response (FIR) filtering.
 23. The method of claim 13 whereinsaid frequency band is determined to be low interference and saidfrequency band expected to experience high interference is determined tobe high interference according to regulation of each of said frequencybands by a governmental entity.
 24. The method of claim 23 wherein saidgovernmental entity is the FCC.
 25. A method for increasing wirelesscommunication capacity, said method comprising: providing a basestation, said base station adapted to transmit data in an expected lownoise frequency band and to receive data in an expected high noisefrequency band; and providing a plurality of subscriber stations, saidplurality of subscriber stations adapted to transmit data in saidexpected high noise frequency band and to receive data in said expectedlow noise frequency band; wherein said base station performs higherorder filtering on signals received at said base station than saidplurality of subscriber station perform on signals received at saidplurality of subscriber stations.
 26. The method of claim 25 wherein thefiltering performed at said base station is performed by a multi-polefilter.
 27. The method of claim 25 wherein the filter performed at saidsubscriber station is performed by finite impulse response (FIR)filtering.
 28. The method of claim 25 wherein the filter performed atsaid subscriber station is performed by surface acoustical wave (SAW)filtering.
 29. The method of claim 25 wherein said low noise frequencyand said high noise frequency band are separated by at least one octave.30. The method of claim 25 wherein said data is frequency divisionduplexed.
 31. A method for increasing capacity of a wireless datacommunication system, said method comprising the steps of: receiving, ata subscriber station, data on a first frequency in a frequency bandexpected to experience low interference; transmitting, at saidsubscriber station, data on a second frequency in a frequency bandexpected to experience high interference; wherein said low interferencefrequency band and said high interference frequency band are separatedby at least one octave; and wherein said transmitting and said receivingoccur during the same communication session.
 32. A method for increasingcapacity of a wireless data communication system, said method comprisingthe steps of: transmitting, at a base station, data on a first frequencyin a first frequency band expected to experience low interference;receiving, at said base station, data on a second frequency in a secondfrequency band expected to experience high interference; wherein saidfirst frequency and said second frequency are separated by at least oneoctave; and wherein said transmitting and said receiving occur duringthe same communication session.